JPH01196302A - Chemical treatment process for timber - Google Patents

Abstract

PURPOSE:To provide flame retardance and enhance dimension stability, hardness and prevention of cracks by impregnating a timber with water-soluble radical polymerized compound water solution essentially containing water-soluble radical polymerized organic acid metal salt and polymerizing the same under the state of water retention. CONSTITUTION:A timber is impregnated with water solution composed of radical polymerized organic acid metal salt water solution in which another water solution radical polymerized compound is mixed, and then heated and polymerized in the state that the water content is scattered over as little as possible. A high molecular compound is modified in the timber by said process and also filled into the spaces of the timber to have water-insoluble organic acid metal polymer contained in the timber and provides flame retardance for the timber. Further, performances such as flame retardance and the like are retained for a long time by being impregnated with water solution inorganic acid salt group.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to the chemical treatment of wood that imparts flame retardancy, texture, and dimensional stability to wood while maintaining the natural cosmetic properties and cuttability of the wood. This relates to a processing method.

(Conventional technology and its problems) As a means of imparting physical properties such as hardness, abrasion resistance, and dimensional stability to wood, so-called resin injection has traditionally been used to fill voids in wood with resin or other compounds. The law is widely known.

According to this method, physical properties such as hardness can be imparted to wood by injecting and solidifying a synthetic resin liquid such as polyester or acrylic, but flame retardance cannot be imparted to the wood.

It is known that wood is impregnated with water-soluble inorganic compounds in order to impart flame retardancy, but this results in deliquescence or elution, which impairs durability.

For this reason, as disclosed in Japanese Patent Application Laid-open No. 61-246003, two types of water-soluble inorganic compounds that produce a desired insoluble and nonflammable inorganic compound when mixed are sequentially impregnated into wood and mixed. Dispersion and fixation of insoluble, nonflammable inorganic compounds has been carried out.

However, since this method simply physically fills the wood voids with water-insoluble inorganic compounds precipitated by the reaction of the above-mentioned treatment liquid, there are problems such as pulverization and falling off or whitening of the surface. There is a point.

Furthermore, since the treatment liquid is contaminated, various industrial steps must be added. Therefore, in order to further improve this, a method of stabilizing it by impregnating it with flame-retardant resins is currently being considered.

[Purpose of the invention]

The present invention was made in view of these problems, and involves impregnating wood with a water-soluble radically polymerizable organic acid metal salt that imparts flame retardancy, thereby combining the wood components and the metal salt within the wood. The purpose is to improve the quality of wood by making it water-insoluble by integrating it.

[Disclosure of the invention]

In order to achieve the above object, the present inventors have conducted various studies and found that a water-soluble radically polymerizable compound containing a radically polymerizable organic acid metal salt as an essential component is capable of forming hydroxyl groups in wood components in the presence of water. Focusing on bonding with active groups such as, we created a polymer with metal crosslinks in wood and firmly integrated it with the wood, and in addition, we created a polymer with metal crosslinks in the wood to firmly integrate it with the wood. Focusing on the ion exchange reaction between inorganic acid salts, we have found that by impregnating wood with a combination of the insolubilized metal crosslinked polymer and water-soluble inorganic acid salts, an extremely excellent wood modification effect can be obtained. This discovery led to the present invention.

That is, the present invention provides a modified wood characterized by impregnating a wood material with an aqueous solution of a water-soluble radically polymerizable compound containing a water-soluble radically polymerizable organic acid metal salt as an essential component and causing a polymerization reaction in a water-retaining state. Production method, impregnating wood material with an aqueous solution of a water-soluble radically polymerizable compound containing a water-soluble radically polymerizable organic acid metal salt as an essential component, polymerizing it in a water-retaining state, and then impregnating it with a water-soluble inorganic acid salt. The present invention relates to a method for chemically treating wood, which is characterized by the following.

The most common radical polymerizable organic acid metal salts used in the method of the present invention are metal salts of (meth)acrylic acid, and among them, sodium acrylate, potassium acrylate, zinc acrylate, barium acrylate, acrylic acid, etc. Acid salts such as calcium acrylate, magnesium acrylate, aluminum acrylate can be advantageously used;
In particular, the polyvalent radically polymerizable organic acid metal salts such as zinc acrylate, barium acrylate, calcium acrylate, magnesium acrylate, and aluminum acrylate become insolubilized by themselves when polymerized, and have good water resistance. .

Although there are various embodiments of the present invention, usually radical polymerizability is determined by preparing an aqueous solution of organic acid metal salt at a concentration of about 20 to 50% at pH 2.
Prepare to about 6.

In addition, although an aqueous solution of the above-mentioned radically polymerizable organic acid metal salt may be used alone, an aqueous solution containing another water-soluble radically polymerizable compound can be integrated with the strong wood material and have a modification effect. It is sometimes used because it improves

Such water-soluble radically polymerizable compounds include:
Glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane triacrylate, polyethylene glycol mono(
Compounds such as meth)acrylate and polyethylene glycol di(meth)acrylate can also be used as crosslinking agents.

The above-mentioned water-soluble radically polymerizable compound is added at a ratio of 0 to 10 parts by weight per 100 parts of the radically polymerizable organic acid metal salt, and ammonium persulfate, potassium persulfate, and persulfate are added as polymerization initiators for an aqueous solution of these compounds. For the total amount of the above compounds using water-soluble peroxides such as hydrogen oxide,
Add 0.01 to 5.0 parts by weight into the aqueous solution.

Incidentally, the above polymerization initiator may be contained in the wood in advance.

Next, this aqueous solution is impregnated into wood such as thin plates, small pieces, blocks, etc. under normal pressure or a combination of reduced pressure, increased pressure, etc.

In this case, if the wood is thick-walled like a block, a surface treatment method such as immersion treatment under normal pressure may be employed in order to impart flame retardancy only to the surface layer.

Immediately after impregnating the wood material with the above aqueous solution, or after being left to cure, heating and polymerization is carried out in a state in which water is not scattered as much as possible.

Specifically, a wooden material is covered with aluminum foil, polyethylene, polyester film, etc., and heated in an oven or autoclave, or heated on both sides with a hot press. Alternatively, it may be heated by steaming in an autoclave.

At this time, the heating temperature is desirably a gentle condition in which the polymerization reaction proceeds without forming banks due to retained moisture, and is preferably about 60 to 150°C, preferably about 80 to 110°C.

In this way, the polymerization reaction occurs in a water-retaining state by modifying the side chains of the wood component with a polymer compound through an addition reaction between active groups such as hydroxyl groups in the wood component and a radically polymerizable organic acid metal salt. This is because we focused on what is possible.

After the polymerization reaction in a water-retaining state, the wood material is subsequently or separately dried to an appropriate moisture content.

The above method is the first method for producing modified wood according to the present invention, and since the treatment liquid is an aqueous solution, it penetrates into the minute voids in the wood while swelling the wood, and in the presence of water. As a result of the addition reaction between the radically polymerizable organic acid metal salt and the active group in the wood component, the wood component is modified with the polymer compound and at the same time, the wood pores are filled into the water-insoluble organic acid metal salt polymer. is contained in the wood material, imparting flame retardancy.

In particular, organic acid salt polymers of polyvalent metals are cross-linked, forming water-insoluble polymers and modifying wood materials, so they are strongly integrated with wood materials and can be used under normal conditions. In this case, the above-mentioned polymer does not elute, and performance such as flame retardancy is maintained for a long period of time. In addition, the wood modified in this manner has the effect of retaining humidity, is dimensionally stable, and has the effect of preventing cracking.

Next, the second method of the present invention will be explained. This method further improves the durability and flame retardancy of the modified wood obtained by the first method, and also has antiseptic and insect repellent properties. This was done to impart this to wood materials.

That is, in the first invention, after a wood material is impregnated with a treatment liquid and polymerized in a water-retaining state, the wood material is subsequently impregnated with a water-soluble inorganic acid or after the wood material is adjusted to an appropriate moisture content. The water-soluble inorganic acid salt is also insolubilized and fixed by impregnating it with salt and performing an ion exchange reaction.

The water-soluble inorganic acid salts include calcium chloride, sodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium ammonium hydrogen phosphate,
Aluminum sulfate, zinc sulfate, sodium silicate, potassium silicate, magnesium chloride, barium chloride, zinc chloride, sodium borate, etc. are used for various purposes such as flame retardant, insect repellent, hardness, and appearance. Depending on the situation, they can be used alone or in combination.

When such water-soluble inorganic acid salts are impregnated into the wood material, the radically polymerizable organic acid metal salt polymer in the wood material and the water-soluble inorganic acid salts undergo an ion exchange reaction to form metal crosslinks. The polymer and inorganic acid salts are insolubilized and fixed in the wood, which not only improves the flame retardance of the wood but also significantly improves its durability.

Next, examples of the present invention will be shown.

[Example 1] 0.0% to a 30% aqueous solution of aluminum acrylate at pH 2.
3% ammonium persulfate was added to prepare an impregnating solution. This impregnating solution was impregnated into a 2nuw thick Hetsuga veneer under a reduced pressure of 30T0■, and the impregnated veneer was covered with aluminum foil and left for 24 hours, followed by a polymerization reaction at 105°C for 3 hours. , and then dried at the same temperature for 2 hours.

The treated veneer thus obtained was extremely hard, had a weight increase rate of 43%, was insect repellent, flame retardant, and had a natural hemlock appearance.

[Example 2] A 3 mm thick Douglas fir veneer was impregnated with a 30% aqueous solution of zinc acrylate at pH 5 and 2% of a 30% hydrogen peroxide solution under a reduced pressure of 30T0RR, and this impregnation treatment was carried out. Cover the veneer with aluminum foil, leave it for 24 hours, and then
The polymerization reaction was carried out at 5°C for 3 hours, and then at the same temperature for 2 hours.
Dry for an hour.

The treated veneer thus obtained was extremely hard, had a weight increase rate of 43%, was insect repellent, flame retardant, and had the natural appearance of Douglas fir.

[Example 3] An impregnation solution was prepared by dissolving 2% trimethylolpropane triacrylate in a 50% aqueous solution of sodium acrylate at pH 6, and further dissolving 0.5% ammonium persulfate as a polymerization initiator. was impregnated into a 2-inch-thick Japanese hemlock veneer under reduced pressure using 3QTOIIK. After covering this impregnated veneer with aluminum foil and leaving it at room temperature for 24 hours,
Polymerization reaction was carried out at 105°C for 3 hours, and then zinc chloride 20
%, borax was soaked in a 3% aqueous solution of 30 TolK again.
After being impregnated with the aqueous solution under reduced pressure and aging for 24 hours, the veneer was washed with water and dried for 12 hours at 105'C to obtain a hard flame-retardant treated veneer with insect repellent properties.

[Example 4] A 50% aqueous solution of barium acrylate with a pH of 5.5 and 1% of a 5% hydrogen peroxide solution (anti-polymerizable salt) was used as an impregnating liquid, and this impregnating liquid was used to coat a 11-thick Japanese hemlock veneer. to 30T0
After impregnating the veneer with the impregnating liquid under a reduced pressure of 11R, the veneer was covered with aluminum foil, left for 24 hours, and then heated at 105°C for 3 hours.
The polymerization reaction was carried out for a period of time, and then the aluminum coating was removed and dried at the same temperature for 2 hours.

The treated veneer thus obtained has a beautiful white line pattern in the wood grain, is extremely hard, has a weight increase rate of 85%, and is resistant to corrosion.
It has earthy properties and flame retardancy, making it an excellent flooring material.

[Example 5] The treated veneer obtained in Example 4 above was impregnated with a saturated aqueous ammonium dihydrogen phosphate solution, allowed to stand for 24 hours, and then further dried.

The treated veneer thus obtained had a weight increase rate of 95%,
It has insect repellent and flame retardant properties, and the white pattern of the wood grain is even more beautiful and emphasized. Further, when this veneer was immersed in distilled water for 24 hours and the weight loss after drying was examined, it was approximately 2%, indicating that the impregnating agent was stabilized.

〔Effect of the invention〕

As described above, according to the method for chemically treating wood of the present invention,
Compounds such as water-soluble radically polymerizable organic acid metal salts combine with active groups such as hydroxyl groups in wood components in the presence of water to produce polymers with metal crosslinks in the wood, which firmly integrate with the wood. It can impart long-term flame retardancy to wood and improve dimensional stability, hardness, crack prevention, etc. Furthermore, the radical polymerizability can be improved by combining organic acid metal salts and water-soluble Water-soluble inorganic acid salts are made insolubilized through an ion exchange reaction with water-soluble inorganic acid salts, and by fixing them in that state, the durability and flame retardance of wood can be further improved, as well as antiseptic and insect repellent properties. can be applied to wood.

Claims (2)

[Claims] (1) A method for chemically treating wood, which comprises impregnating wood with an aqueous solution of a water-soluble radically polymerizable compound containing a water-soluble radically polymerizable organic acid metal salt as an essential component, and causing a polymerization reaction in a water-retaining state. . (2) Impregnating wood with an aqueous solution of a water-soluble radically polymerizable compound containing a water-soluble radically polymerizable organic acid metal salt as an essential component, polymerizing it in a water-retaining state, and then impregnating it with a water-soluble inorganic acid salt. A chemical treatment method for wood characterized by: